Lumbosacral and Spinopelvic Anatomy and Pathology - Mid Pedicle Level L5

Lower lumbar spine from a 45–year–old woman at the mid–pedicle level of L5. At L4–L5 and L5–S1 the large dorsal root ganglia occupy the subpedicular notches of the foramina (root canals) and are bordered superiorly by the pedicles and posteriorly by the ligaments flava Ooint capsules). At both levels the much smaller motor roots can be distinguished from the ganglia. The upper portion of the foramina carries the segmental arteries and veins. The discs have a dark outermost annular layer of collagen fibers that resemble a capsule. At L4–L5 the ligamentum flavum divides into two layers: the vertical portion extends laterally and terminates with a sharp lateral border, the posterior extension merges with the capsule of the facet joint. Note the dark collagenous inferior capsule of the L4–L5 facet joint.